(1) Field of the Invention
The present application relates to an apparatus for collection and conversion of wave energy in a fluid mass, said apparatus comprising a frame including a hinged vertically tilting surface, such as a barrier in the form of a panel or a sail, for collecting energy from passing wave pressure fronts and liquid particle motion via a tilting or rotating motion within the frame, wherein the hinge is positioned below the surface of the fluid at the trough of the respective waves, said barrier in the form of a panel or a sail being connected to a device capable of converting the tilting motion or rotational motion into different types of energy. According to an example of embodiment, the apparatus will be positioned as perpendicular as possible to the direction of travel of the waves and will be placed at a depth such that the tilting or rotating barrier in the form of a panel or a sail barely breaks the surface of the fluid at the crest of the respective waves. According to other aspects of the present invention, the apparatus according to the present invention may be positioned at other depths as well. The frame and/or barrier in the form of a panel and/or a sail preferably includes vertically positioned side walls for directing the pressure fronts of passing waves in towards the tilting barrier in the form of a panel or a sail. The expression “breaks the surface of the respective waves” means that the top of the barrier preferably lies within some boundaries from the crest of the respective waves, wherein the boundaries are defined according to practical considerations for the actual application of the apparatus. According to an example of embodiment, the height of the barrier above the water will be adjusted to suit the height of the actual waves from which the energy is to be collected, i.e., in relation to, for example, the weather conditions at the geographical location where the apparatus is installed, the current and bottom conditions at the relevant geographical area etc. However, the design of ocean deployed power plants must take into consideration a plurality of additional design constraints other than as effectively as possibly converting wave power into for example electric power.
The environment at open sea can be extreme, for example, the mechanical construction of the power plant must withstand what is known as the 100 year wave, which can destroy almost any installation at open sea. These design criteria and other environmental considerations provided for in official regulations can make the economy of the wave power plant unprofitable. Therefore, it is also an objective of the present invention to provide a wave power plant that is cheap to manufacture and maintain, and that at the same time is robust enough to withstand harsh environmental conditions.
The world has an enormous need for energy sources that does not pollute and is renewable, and, as such, energy from the ocean and the air appears to be an excellent option. Energy from the air is currently harnessed via windmills, but even though a number of installations and apparatus for collecting and converting energy from waves in the ocean and from lakes are known, the net output of such wave-energy collecting and converting installations and apparatus is still too small to be economically warrantable.
(2) Description of Related Art
Apparatus are previously known which attempt to collect energy from the ocean, so-called energy installations, which convert wave energy and also tidal energy into, for example, electric power which exploits the horizontal pressure differences transported by such waves in the water masses as well as tidal differences at the surface of the ocean.
For instance, from US Patent Application 2004/0007881 A1 there is known an energy collecting device which generates energy from vertically travelling pressure waves or fronts in the sea in order to operate a device for reverse osmosis so as to generate fresh water. In this application it is proposed that the apparatus be placed at a depth that is L/2 below the surface, where L represents the wave length of the relevant waves from which the energy is to be collected. The vertically positioned surface that is to collect the wave energy is disclosed as a rectangular panel that stands vertically in the body of water and which drives a horizontally positioned hydraulic pump via a lever arm.
From U.S. Pat. No. 4,371,788 there is known an apparatus for collecting vertical, horizontally travelling pressure waves in the water masses, where the energy is collected using a vertical sail or panel that is located in the surface region of the water masses. It is explained that such an apparatus is connected to mechanical means in order to collect the energy.
Although the prior art is capable of generating energy from horizontally travelling pressure waves in the water masses, none of them include any suggestion of an optimal configuration or design of the collecting surface (barrier). Furthermore, all such apparatus according to the prior art are either hinged above the water and collect wave energy via a tilting action of the barrier in the form of a panel projecting down from the hinge (and do not fully exploit the travelling pressure waves in the water masses), or they are hinged below the surface of the water, but the apparatus is located on the floor of the ocean or the lake and is thus not equipped to exploit the full energy potential of the travelling pressure fronts in the liquid mass (see the explanation below).
Thus, there is a need for an apparatus for optimal collection of wave energy from a fluid medium (sea, ocean or lake) both from small or medium-sized waves (0.5-2 m amplitude) and from large-sized waves (more than 2 m amplitude).